Not Applicable
Not Applicable
Not Applicable
1. Background of the Invention
This invention relates to a variable mode; turbofan, turbojet and ramjet type jet engine, which is suitable for compact installation. Jet engines are normally built in fixed mode either as turbofans, turbojets or ramjets, this invention sets out to combine all types of engine.
2. Brief Summary of the Invention
According to the present invention there is provided a jet engine comprising of a complete low bypass turbofan unit including secondary fan unit and engine core; compressor, combustion chambers, turbines and secondary bypass duct. Some five to eight feet ahead of which sits a larger diameter main fan unit, driven from the front of the turbofan via a short drive shaft. Between the main fan and the secondary fan sits a reversed front inner variable area nozzle, connected to the forward end of the secondary fan in line by a short inlet tube. The nozzle is arranged to form a ram from the main fan into the secondary fan when open. At the back of the engine core sits another, rear inner, variable area nozzle facing rearwards in line. The whole of this arrangement; front inner nozzle, inlet tube, secondary fan, engine core, secondary bypass duct and rear inner nozzle, is enclosed by a variable diameter cylinder, providing a main variable area bypass duct between the cylinder and the engine outer casing, which extends backwards from the outer diameter of the main fan and completely encloses the cylinder within. A third, main, variable area nozzle is positioned aft of the outer casing facing rearwards. An intercooler is fitted in line in or around the inlet tube just ahead of the secondary fan to cool down the incoming air charge.